Also, he said we were lucky because it's one of 6 (IIRC), and the easiest one to get to. The others require much more dismantling and a few more man hours. Got the old core plug out too, amazing how much it had corroded on one side. Make sure you refresh your antifreeze/coolant regularly!!

Thanks everybody. Took it along with the knowledge that it was the core plug. I was charged £40 to replace it, refill with anti-freeze and get rid of the airlocks. The last but took a while but it wasn't as disastrous as I first thought when I saw steam pouring up through the bonnet! Thanks again for all your suggestions. Super!

Help required... Car details: Fiesta MK5 (2001) Endura-E 1.3 engine. Steam started coming up from under the bonnet yesterday and we discovered a small jet of coolant spraying from inside the engine. At first we thought it was the pipe heading in to the oil filler cap, but on further inspection there is a hole in the engine block which is spraying out water when the engine is hot. I've attached a photo of the offending hole. I'm sorry that there isn't much context to it as it's a bit of a close up. If you can't tell where it is I can try to describe it... As you look into the engine bay from the front of the car, it is on the right-hand side, vertical part of the engine block. What I ask is, how easily can this be repaired? Anybody with any experience of this? Cheers, Liam